Semiconductor gas sensor of ammonia trace impurities
FIELD: measuring equipment.
SUBSTANCE: invention relates to gas analysis, in particular, to devices used for recording and measuring the content of ammonia trace impurities. Sensor includes a semiconductor base and a substrate. Semiconductor base is made from a polycrystalline film of indium antimonide doped with cadmium telluride – (InSb)0.98(CdTe)0.02, and the substrate used is an electrode pad of a piezocrystal resonator. Proposed sensor with considerable simplification of its manufacturing technology makes it possible to determine the content of ammonia with a sensitivity several times higher than that of existing sensors.
EFFECT: technical result is higher sensitivity and manufacturability of the sensor.
1 cl, 3 dwg
SUBSTANCE: safety of articles made of phenol-formaldehyde plastic is evaluated using a multichannel gas analyser (MAG-8) with 8 piezo-quartz resonators, the electrodes of which are modified by applying solutions of polydiethylene glycol succinate, polyethylene glycol sebacate, polyethylene glycol phthalate, polyphenyl ether, trioctylphosphine oxide, bee glue, beeswax and a composite sorbent - bee glue with iron (III) chloride. The mass of the sorbent film is 15-20 mcg after removing the solvent at 40-50°C for 15-20 min. The modified piezo-quartz resonators are then placed in the closed detection cell of the MAG-8 and held for 5 min to establish a stable zero signal. Further, 5.00 g of a ground sample of phenol-formaldehyde plastic is placed in a sampler which is then tightly closed with a polyurethane plug and held at 20±1°C for 15 min to saturate the gas phase with phenol vapour. Further, 3 cm3 of the equilibrium gas phase is collected through the polyurethane plug and injected into the closed cell of the MAG-8, followed by measuring the change in the oscillation frequency of the piezo-sensors for 120 s and calculating the area of the "visual print" Sv.p., Hz·s, using the formula Sv.p.=f(Cph), S=1959·Cph+35. For the calculation, a calibration curve of Sv.p., Hz·s versus phenol concentration Cph, mg/dm3 is plotted first. If the area Sv.p.≥130±10 Hz·s, the concentration of free phenol in the equilibrium gas phase over the phenol-formaldehyde plastic Cph>0.05 mg/dm3 exceeds the recommended level for food plastics, and if Sv.p.>260 Hz·s or higher, high content of phenol and formaldehyde is recorded.
EFFECT: invention provides fast evaluation of safety of articles made of phenol-formaldehyde plastic.
2 dwg, 1 ex
SUBSTANCE: semi-conductor gas analyser of carbon monoxide contains a semi-conductor base, applied on a non-conductive substrate, with the semi-conductor base being made from a polycrystalline film of a solid solution (ZnTe)0.26(CdSe)0.74.
EFFECT: increase of the sensitivity and technological efficiency of the sensor production.
FIELD: measurement equipment.
SUBSTANCE: invention relates to the field of gas analysis, in particular, to detecting devices used for registration and measurement of oxygen content. A gas sensor according to the invention comprises a dielectric substrate with the applied layer of the semiconductor material with thickness from 0.07 mcm to 0.2 mcm. Metal electrodes are applied onto the layer. Semiconductor material is polycrystal material of composition Sm1-xLnxS, where x changes from 0 to 0.14, and Ln is one of elements: La, Ce, Pr, Nd, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu.
EFFECT: invention makes it possible to make a sensor for measurement of oxygen content having higher sensitivity.
2 cl, 3 dwg, 4 ex
SUBSTANCE: in formation of films for determination of content of water vapour in air medium successive application of poly-N,N-dimethyl-3,4-dimethylenepyrrolidinium chloride is realised on the surface of oxide glass by aerosol spraying and potassium hexacyanoferrate (III) - by ultrasonic spraying in ratio 3:1 with formation of poly-N,N-dimethyl-3,4-dimethylenepyrrolidinium cyanide film, selective with respect to water vapour.
EFFECT: providing possibility to obtain thin films of controlled thickness, increase of film stability, selectivity on the surface of oxide glass with respect to content of moisture in air medium and improvement of metrological characteristics of measurement of electric conductivity value.
SUBSTANCE: invention comprises producing nano-heterogeneous material based on whisker crystals of n-type oxides SnO2, ZnO, In2O3 and nano-clusters of p-type oxides CuO, NiO, Co3O4 immobilised on the surface of said crystals. The method includes producing whisker crystals from vapour and impregnating the crystals with salt solutions, followed by annealing to form p-n heterocontacts.
EFFECT: high selective sensitivity of the sensor to H2S and derivatives thereof in air.
3 cl, 2 ex
FIELD: measurement equipment.
SUBSTANCE: invention relates to manufacture of gas sensors intended for detection of different gases. The invention proposes a gas sensor manufacturing method, in which a heterostructure is formed of different materials; a gas-sensitive layer is made in it; after that, it is fixed in the sensor housing, and contact pads are connected to terminals of the housing by means of contact conductors. The gas-sensitive layer is made in the form of a thin tread-like nanostructure (SiO2)20%(SnO2)80%, where 20% - mass fraction of SiO2, and 80% - mass fraction of component SnO2, by application of sol of orthosilicic acid, which contains stannum hydroxide, onto a silicone surface by means of a centrifuge with further annealing. An area with width of 1 mcm and depth of 200 nm is formed on the surface of the substrate surface by a method of local anodic oxidation. Sol is prepared at two stages: at the first stage, Tetraethoxysilane (TEOS) and ethyl alcohol (95%) is mixed in the ratio of 1:1.046 at room temperature, and the mixture is exposed during about 30 minutes, and at the second stage, to the obtained solution there introduced is distilled water in the ratio of 1:0.323; hydrochloric acid (HCl) in the ratio of 1:0.05; stannum chloride dihydrate (SnCl2·2H2O) in the ratio of 1:0.399, where TEOS volume is accepted as one, and stirred at least during 60 minutes. The invention also proposes a gas sensor with a nanostructure, which is made as per the proposed method.
EFFECT: increasing gas sensor sensitivity.
2 cl, 4 dwg
FIELD: measuring instrumentation.
SUBSTANCE: ammonia trace contamination sensor includes semiconductor base and substrate. Semiconductor base is made out of polycrystalline cadmium sulphide nanofilm reinforced with cadmium telluride. Electrode pad of pieso-quartz resonator serves as substrate.
EFFECT: significantly simpler design of sensor, several times higher sensitivity than that of existing sensors.
SUBSTANCE: sensor contains a semiconductor base and a substrate, with the base being made of a polycrystalline film of cadmium sulphide, alloyed with zinc telluride, applied on the non-conducting substrate.
EFFECT: increase of the sensor sensitivity and manufacturability of its production.
FIELD: measurement equipment.
SUBSTANCE: invention relates to gas analysis and may be used to control toxic and explosive gases and in these areas of science and engineering, where analysis of gas media is required. A semiconductor sensitive element according to the invention represents an isolating substrate with previously applied contacts, on which, by application of a film-forming water-alcohol solution SnCl2 with carbon nanotubes they form a layer of nanocomposite of tin dioxide. The sensitive element manufactured in this manner is exposed to drying for 10 minutes at 150°C with subsequent stabilising annealing on air for 30 minutes at temperature of not below 370°C for formation of the nanocrystalline structure.
EFFECT: invention is aimed at increasing value of gas sensitivity and selectivity of a sensor element.
2 cl, 1 dwg
SUBSTANCE: in accordance with the invention a sensor contains a semiconductor base and a substrate, with the base being made of a polycrystalline film of cadmium telluride, doped with zinc sulphide, applied on the non-conducting substrate.
EFFECT: possibility of increasing the sensor sensitivity and technological effectiveness of its manufacturing.
FIELD: powder-like hard substances analysis.
SUBSTANCE: device has reaction tank, made of non-rusting steel and provided with coat for thermostatting, lids with inbuilt holder for piezoquartz sensor, made of same material, piezoquartz sensor, input branch pipe, air output, reaction tank for detection with 100 sm3 volume. Inside said tank cassette perforated on both sides for samples of powder-like, hard substances and air ventilator for evening concentration of light substances at whole volume of cell are placed. Piezosensor is provided with moving cover, making it possible to actuate sensor with stabilized phase balance.
EFFECT: higher precision.
1 tbl, 1 dwg
FIELD: analytical methods in fuel industry.
SUBSTANCE: method consists in using detector represented by a set of five piezo-sorption mass sensors modified with fixed phases having different sensitivity and selectivity while responses of sensors are recorded in turns. Identification of product is accomplished using "visual imprints" technique.
EFFECT: achieved rapidity in gasoline identification.
15 dwg, 1 tbl, 15 ex
FIELD: gas phase analysis technologies.
SUBSTANCE: device consists of thermostat-processed reaction tank, branch pipes for input and output of carrier gas and sample, reaction tank has two hermetically interconnected cylindrical portions; into upper portion detachable holder is built for 25 piezoquartz sensors and electronic control device, into lower portion perforated case for sample is built as well as air ventilator for removal of concentration gradient of flying compositions along whole volume of cell.
EFFECT: higher precision, higher efficiency, broader functional capabilities.
1 tbl, 1 dwg
FIELD: analytical chemistry.
SUBSTANCE: invention includes forming a matrix of sensors for screening-analysis of air of room, polluted by light compositions of modern construction materials, optimization of operation conditions for poly-sensor matrix, development of algorithm for processing sensor signals and taking a decision concerning air safety of room after maintenance/repair procedures. Method includes forming a matrix of sensors on basis of films of apiezon-N, Triton X-100, bee glue, modified by Fe3+ solution (mass share of Fe3+ 25%), polyethyleneglykoladypinate with masses 10-20 mcg and certain algorithm for registering signals from sensors is used.
EFFECT: higher efficiency, higher precision, higher safety.
9 ex, 2 tbl, 9 dwg
FIELD: atmosphere control technologies.
SUBSTANCE: device has three independent sensors, reacting selectively on certain gas: methane - CH4, carbon monoxide - CO, oxygen - O2, microcomputer, clock and interface device with PC. Information taken from sensors is transformed to digital code and sent to computer display. Device includes time count, recording of data in unified base and comparison to maximally allowed concentrations of these substances.
EFFECT: broader functional capabilities, higher information yield.
FIELD: technologies for controlling hazardous admixtures in atmosphere.
SUBSTANCE: device integrates on one side of crystal a heater of special shape, concurrently used as thermal resistance and two gas-sensitive elements, one of which is covered by gas-impenetrable layer and serves as a comparison element in measurements. To provide for even distribution of temperature along crystal heater in form of H letter is positioned not only along perimeter but also in the center of crystal.
EFFECT: broader functional capabilities, higher efficiency.
FIELD: hygrometers with bolometric heat sensitive member, stove or furnace using such hygrometer and method for controlling stove or furnace.
SUBSTANCE: hygrometer includes two static bolometric heat sensitive members for accurate detection of humidity value. Stove or furnace includes bolometric hygrometer secured to one side of bracket in air discharge opening for deflecting direction of air flow in order to detect humidity value at high accuracy in cooking chamber. Method for controlling operation mode of stove or furnace provides different periods of heat treatment of food products in package or without it.
EFFECT: enhanced accuracy of humidity measuring.
13 cl, 15 dwg
FIELD: investigating or analyzing materials.
SUBSTANCE: gas analyzer comprises housing made of a cylinder, which is provided with two lids having holders for twelve piezoelectric sensors arranged over periphery and provided with different film coatings made of sorbents for fixing the principal components of the gas mixture, and device for excitation of vibration and receiving signals from the piezoelectric sensors. The branch pipes for supplying and discharging gas mixture are arranged along the horizontal axis of symmetry of the housing and provided with the polyurethane spacers and detachable plugs. The lids are connected with the cylindrical housing via the thread.
EFFECT: simplified method of analysis and expanded functional capabilities.
3 dwg, 1 tbl
FIELD: gas analysis, in particular, detecting devices used for registration and measurement of content of micro-admixtures of nitrogen and other gases.
SUBSTANCE: in the sensor, containing semiconductor base and substrate, semiconductor base is made of polycrystalline film of cadmium telluride, alloyed with indium antimonide, and as substrate, electrode platform of piezo-quartz resonator is utilized.
EFFECT: increased sensitivity and manufacturability of sensor manufacture, expanded functional capabilities of sensor.
FIELD: gas analysis, in particular, engineering of detecting devices, used for registration and measurement of content of micro-admixtures of nitrogen and other gases.
SUBSTANCE: sensor has substrate and semiconductor base. Substrate is made of piezo-quartz resonator, and semiconductor base - of polycrystalline film of cadmium telluride, applied to electronic area of piezo-quartz generator.
EFFECT: increased sensitivity and manufacturability of sensor, expanded functional capabilities of the same.